The diet – which hit No. 1 on the New York Times bestseller list – is pretty simple: Divide your meals among low-fat protein (one-third of your plate) and vegetables and fruits (the other two-thirds). You’re allowed a tiny amount of fat: olive oil and fats low in omega-6.

How it works:

Zone dieters are allowed a small portion of protein (a small chicken breast, for example) with every meal and snack ( the latter twice daily). You’re also allowed “favorable carbs” such as most vegetables, fruits, beans, whole grains and beans, two times the portion of your protein intake.